Structure for fixing screen bars of screening apparatus for wastewater treatment

Abstract

Disclosed herein is a structure for fixing screen bars of a screening apparatus, which is installed in a wastewater treatment plant to remove impurities contained in wastewater and includes a screen panel formed by arranging the screen bars parallel to each other to have gaps ranging from 1 mm to 10 mm therebetween. The screen bar fixing structure of the present invention is constructed such that screen bars, which are thin and long shapes, can maintain the straightness and gaps therebetween constant even though the screen bars are not welded to support bars provided on the rear surfaces of the screen bars, thus solving the problem in which impurities such as hairs, which are relatively long, are wound around the support bars, with the result that rakes undesirably flip or are damaged, or the gaps between the screen bars become clogged.

1. A screening apparatus usable in a wastewater treatment plant to remove impurities contained in wastewater, comprising:
 a. a frame, 
 b. a screen panel attached to said frame and formed of
 i. screen bars having upper and lower ends and front and rear surfaces and said screen bars being arranged parallel to each other to have gaps ranging from 1 to 10 mm therebetween, and 
 ii. upper and lower spacer bars extending transversely at the opposite ends respectively of said screen bars and coupled thereto, 
 
 said screen panel having front and rear surfaces defined by said corresponding front and rear surfaces of said screen bars, 
 c. a plurality of rakes movable along said front surfaces of said screen bars to rake impurities caught by said screen panel, 
 d. a drive system attached to said frame to move said rakes, and 
 e. an impurity guide attached to said frame adjacent upper end of said screen panel to receive said impurities raked off said screen panel, wherein, 
 the lower end of each of said screen bars includes a notch being connectible with clearance to one of a plurality of fastening holes formed on said lower spacer bar, and wherein said upper end of each of the screen bars comprises a fastening part formed by bending a part of the upper end of the screen bar toward the rear surface of the screen bar which is inserted into a through hole formed in said impurity guide, such that the upper ends of the screen bars are prevented from interfering with the linear travel track of the rakes, and 
 wherein said screen bars have medial portions between their opposite ends, said apparatus further comprising support bars positioned closely adjacent the rear surfaces of said screen bars at the medial portions thereof and oriented in a direction perpendicular to the screen bars to prevent the medial portions from sagging. 
 
     
     
       2. The structure for fixing the screen bars of the screening apparatus for wastewater treatment as set forth in  claim 1 , wherein the lower ends or the upper ends of the screen bars are fitted into respective fastening holes with clearances, so that the screen bars remain straight without bending due to a difference in thermal expansion between the screen bars and side-frames of the screening apparatus. 
     
     
       3. Apparatus for screening impurities from a flow of wastewater in a wastewater treatment plant, said apparatus comprising:
 a. a frame having opposite sides and opposite lower and upper ends, 
 b. a screen panel attached to said frame and comprising a plurality of elongated screen bars situated generally parallel to each other and spaced apart from each other defining a gap between adjacent screen bars in the range of 1-10 mm, said screen bars having front surfaces which the define the front surface of said screen panel that receives said wastewater flow, 
 c. a plurality of rakes, each extending transversely across the front surface of said screen panel, said rakes being generally parallel to each other and spaced apart from each other, and 
 d. a drive system coupled to and driving said rakes in successive paths lengthwise along said front surface of said screen panel, where each of said rakes extends into and along one of said gaps between two adjacent screening bars, 
 each of said screen bars having a lower end coupled in a lower coupling to said lower spacer bar and an opposite upper end coupled in an upper coupling to said upper spacer bar, 
 said lower couplings releasably holding with clearance said lower ends of said screening bars, and 
 said upper ends of said screen bars being bent away from the plane of the screen panel and thus prevented from interfering with the linear travel path of said rakes, and 
 said apparatus further comprising a plurality of support bars extending transversely across said screening panel below and supporting said screening bars, wherein each of said lower couplings comprises a notch in the lower side of the lower end of each screen bar and one of a plurality of openings in said lower spacer. 
 
     
     
       4. The apparatus according to  claim 3  wherein said lower couplings comprise openings in said lower spacer bar formed by spaced apart notches and a board overlying each of said notches and secured thereto. 
     
     
       5. The apparatus according to  claim 3  wherein said rakes are attached to a belt formed as an endless loop, said belt being driven in a loop path by said drive system. 
     
     
       6. A structure for fixing screen bars of a screening apparatus for wastewater treatment, the screen bars having upper and lower ends and medial portions, the screening apparatus being installed in a wastewater treatment plant to remove impurities contained in wastewater, the screening apparatus comprising:
 a screen panel formed by arranging the screen bars parallel to each other to have gaps ranging from 1 mm to 10 mm therebetween, 
 rakes movable along a front surface of the screen bars, and 
 drive means to move said rakes to rake the impurities caught by the screen panel, 
 wherein a notch is formed in the lower ends of the screen bars, the notch is fastened to a fastening hole formed on the lower spacer formed in a rear part of a lower end of the screening apparatus, 
 the upper end of each of the screen bars comprises
 an inclined part formed by bending a part of the upper end of the screen bar towards the rear surface of the screen bar, and 
 a horizontal part formed by bending an end of the inclined part in a horizontal direction, 
 
 wherein the horizontal parts of the screen bars are inserted into through holes, which are formed in an impurity guide, and are fitted into respective fitting holes in an upper spacer which is disposed below the impurity guide such that the upper ends of the screen bars are prevented from interfering with the linear travel track of the rakes, 
 and said medial portions of the screen bars are supported by support bars, oriented in a direction perpendicular to the screen bars, to prevent the medial portions of the screen bars from sagging. 
 
     
     
       7. The structure according to  claim 6 , wherein the lower ends or the upper ends of the screen bars are fitted into respective fitting holes with clearances, so that the screen bars remain straight without bending due to a difference in thermal expansion between the screen bars and side-frames of the screening apparatus.